Is MRI Contrast Injection Into a Joint Safe?

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Magnetic resonance imaging tests (MRIs) are commonly used by orthopedic surgeons to evaluate a variety of conditions. MRIs can be particularly helpful at providing a visual image of different tissues within the body. By allowing your physician to "see" tissues including muscle, tendon, cartilage, bone, and ligaments, structural damage to the musculoskeletal system can be evaluated.

MRIs are commonly used to identify rotator cuff tears in the shoulder, anterior cruciate ligament injuries in the knee, and a variety of other orthopedic conditions throughout the body.

While MRIs may not be the best test in every clinical setting, they are a useful test that can be used to evaluate a variety of conditions.

There are situations where an MRI may be performed with something called "contrast enhancement." Contrast is a substance they can be added to different areas of the body to make them more visible on a scan. For example, sometimes contrast is injected into the bloodstream to better illustrate the location of blood vessels on the MRI. Contrast can also be injected within the joint to help detect more subtle ligament and cartilage injuries. With these procedures, however, a question is often asked: Are contrast solutions safe?

Gadolinium Enhancement

The most commonly used contrast agent for an MRI test is called gadolinium. Gadolinium is a rare earth metal that can be used in healthcare settings to highlight specific findings on MRI tests. A small amount of gadolinium can be injected into the bloodstream or injected into a joint to provide contrast enhancement to an MRI.

Other types of contrast agents are used for other types of imaging tests. For example, people having x-rays or CT scans often have contrast agents, but these are not gadolinium based. For most radiographic studies, the contrast is iodine-based.

For orthopedic conditions, the most commonly use type of contrast enhancement is called MRI gadolinium enhanced arthrography.

This means that the contrast solution, the gadolinium, is injected inside of the joint. By injecting contrast within the joint, it becomes easier to visualize damage to cartilage and ligaments. Contrast enhancement can be used for many different types of MRIs, but the most common reasons to get a contrast enhanced MRI include:

As mentioned, contrast enhancement can be used for other reasons, these just are some of the more common reasons why your orthopedic surgeon may ask for the test to be contrast enhanced.

Is Contrast Safe?

There has been some recent interest in the safety of gadolinium injected into the body. Most of the research in question has to do with injection of gadolinium into the bloodstream, so there is very little data looking into the safety of injection of gadolinium into a joint. The concern with injection into the bloodstream is that gadolinium can accumulate and persist in certain tissues of the body. There has also been an association with gadolinium causing worsening of kidney disease in certain people. While this is not a common side-effect, it does raise the possibility of concern.

Most studies have shown that gadolinium is a safe substance to use, even during pregnancy. As long as people do not have active kidney disease, injections of gadolinium are considered to be safe. While this substance should not be used routinely, it can be a helpful tool to help diagnose a variety of conditions.

There are also some research studies that show evidence that gadolinium injections into the joint can cause joint inflammation and irritation.  It is not clear that the gadolinium is the actual culprit, and the reason people get joint inflammation after these injections may be the result of the volume of fluid administered, or other substances injected along with the gadolinium.

However, having the injection, whatever the cause, can lead to increased symptoms of joint pain.

Is a Contrast Injection Necessary?

This is probably the bigger question: Is gadolinium arthrography necessary to make the diagnosis of a labral tear or a Tommy John injury? This is a subjective debate, and it is also a subject that is changing as MRIs improve in their quality. There is no doubt that contrast-enhanced MRIs used to be much more effective at making the diagnosis of certain types of injuries than noncontrast MRIs. However, MRIs are getting much more accurate, and the difference between contrast enhancement and a noncontrast MRI may not be as significant as it used to be. There is newer data showing a contrast enhancement is probably not necessary to make many common orthopedic diagnoses.

What to Do?

If your doctor is suggesting a contrast enhanced MRI, it is reasonable to ask them if the contrast enhancement is really necessary. As mentioned, with newer MRI machines that provide better quality images, the need for intra-articular contrast enhancement is becoming less significant. There are undoubtedly times when contrast enhancement is a better option, but these are relatively infrequent and the vast majority of MRI tests can be performed without contrast enhancement.

People who have underlying kidney disorders should make sure their physician is aware of this issue prior to undergoing any MRI test. In addition, it is reasonable to ask your physician what the benefit of a contrast-enhanced MRI—compared to a non-contrast-enhanced MRI test—would be. If this difference is minimal, then you may want to consider not having gadolinium injected into your body.

A Word From Verywell

Contrast injections can help with some MRIs to make them more accurate to diagnose specific conditions. However, there are possible risks associated with contrast materials, and some of those risks may not be completely understood. If contrast enhancement has been recommended, it should be clear to both your physician and to you why the added risk provides sufficient benefit. If there is no clear reason to utilize contrast enhancement, most modern MRIs can accurately diagnose the vast majority of orthopedic conditions without this added risk.

Sources:

Firth, S. "FDA Panel Backs New Warning for Gadolinium Contrast Agents" MedPage Today. September 11, 2017.

"Gadolinium-based Contrast Agents for Magnetic Resonance Imaging (MRI): Drug Safety Communication - FDA Evaluating the Risk of Brain Deposits With Repeated Use" FDA Statement. July 27, 2015.

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